Multi-zone golf club heads

ABSTRACT

A golf club head with low and high density zones designed to provide specific densities for use in various parts of the club head to achieve maximum volume and properties within specific weight goals. The low and high density zones may be formed from laminates having different equivalent densities than the layers used to form the laminates.

FIELD OF THE INVENTION

The present invention relates to a golf club head comprising zonesdesigned to provide specific densities for use in various parts of theclub head to achieve maximum volume and properties within specificweight goals. More specifically, the present invention relates to a golfclub head with properties that may be manipulated based on zones in theclub head that are formed from laminates having different overalldensities.

BACKGROUND OF THE INVENTION

Golf club designers are constantly manipulating the shape, size, andmaterials used to manufacture clubs in an effort to maximizeperformance. For example, fairway woods and hybrids typically have asimilar overall mass as a driver, but less than half the volume of adriver. In particular, modern drivers are approximately 460 cc, whereasmodem fairway woods range from approximately about 150 to 180 cc.Therefore, manufacturers typically use stainless steel materials forfairway woods and hybrids since the high density of steel provides adesirable mass distribution for the smaller head size. However, thesmaller size of the face in fairway woods and hybrids makes it difficultto achieve maximum coefficient of restitution when using stainless steelbecause the elastic modulus is relatively high, and the face must remaina certain thickness in order not to compromise the durability.

While other lower density materials such as titanium or aluminum-basedmaterials may be used to make the fairway wood, which increases the CORof the club head because of the lower modulus of the material, the lowdensity of the material necessitates additional mass that must be addedto meet the target head weight. Indeed, to achieve desirable massproperties in fairway woods, much of the discretionary mass is drivenboth toward the perimeter and low on the sole with the use of weightshidden within the club head. When made from titanium, the weights mustbe large and incorporated on the sole to keep the center of gravity(COG) as low as possible. However, the moment of inertia (MOI) (theresistance to twisting of any golf club head when the golf ball isimpacted off center) may suffer with such a design and the largeconcentrated mass in the center of the sole may lead to acoustic issues.While other materials may be used for the weights, the bonding ofnon-titanium weights to a titanium-based club head is difficult toachieve with dissimilar metals. Alternatively, manufacturers haveattempted to use higher density materials such as steel to form the soleof the otherwise titanium-based club head. However, creating a robustmetallurgical bond around the perimeter of the steel plate is highlyproblematic.

Other types of clubs have similar issues. In fact, as drivers haveincreased in volume, their MOIs have also increased providing “largersweet spots” and more forgiveness on off-center hits. However, when thevolume is maximized through spatially distributing the mass in all threeorthogonal orientations, the COG is positioned substantially rearwardfrom the front face of the golf club head and high, which renders shotsstruck off-center from the sweet spot of the golf club head undesirableas a result of the increase in backspin. And, when weight members areattached to manipulate the COG, the club may become heavy and unwieldy,possibly to the point of limiting a golfer's swing speed and adverselyaffecting the golfer's swing mechanics. Similarly, efforts to manipulatethe distribution of material in a club head with low and high densitymaterials in various portions of the club head may impact the COR of theclub head depending on how the material is distributed in the club head.

It would be advantageous to a provide materials for golf clubs thatmaximize the internal mass distribution and volume of the club headdepending on the shape, size, and performance requirements of theparticular club head. In addition, it would be beneficial to minimizethe elasticity on the face to increase COR while still using a facematerial that has high strength since the face is a high stress area.Furthermore, there is a need in the art for materials that are capableof being joined to each other via conventional or unconventionalmethods. The present invention provides materials, golf club headsincluding the materials, and methods of making the golf club heads thatincludes the materials to achieve the proper balance between massdistribution and club head performance.

SUMMARY OF THE INVENTION

The present invention relates to a golf club head, including: a firstzone including a body defining an inner volume, sole, and a skirt,wherein the first zone has a first density ranging from about 3 g/cm³ toabout 4 g/cm³, and wherein the first zone is formed from a firstlaminate, wherein the first laminate includes a first layer and a secondlayer, and wherein the second layer faces the inner volume; a secondzone including a crown, wherein the second zone is formed from a secondlaminate having a second density ranging from about 3 g/cm³ to about 4g/cm³, wherein the second laminate is different from the first laminate;and a third zone including a face, wherein the third zone includes athird laminate including three layers.

In one embodiment, the second density is different from the firstdensity. In another embodiment, the first layer has a density rangingfrom about 3 g/cm³ to about 4 g/cm³ and the second layer has a densityranging from about 2 g/cm³ to about 3 g/cm³. In still anotherembodiment, the first layer has a first thickness from about 0.1 mm toabout 0.5 mm, and wherein the second layer has a second thicknessranging from about 0.4 to about 0.8. In yet another embodiment, thefirst layer has a first thickness, wherein the second layer has a secondthickness, and wherein the ratio of the first thickness to secondthickness ranges from about 1:1 to about 1:4.

The second laminate may include a third layer having a third density anda fourth layer having a fourth density, wherein the fourth density isless than the third density, and wherein the fourth layer faces theinner volume. In one embodiment, the third layer has a third thicknessand the fourth layer has a fourth thickness, and wherein the fourththickness is greater than the third thickness.

The golf club head may include one or more weights and one or morecorresponding weight ports.

The present invention also relates to a golf club head that includes abody defining an inner volume, a sole, a skirt, a crown, and a face,wherein the sole includes a first zone, wherein the first zone has afirst density ranging from about 5.5 g/cm³ to about 7 g/cm³, wherein thecrown includes a second zone, wherein the second zone has a seconddensity less than the first density and ranging from about 3 g/cm³ toabout 4.5 g/cm³, and wherein the face includes a third zone.

In one embodiment, the first zone includes a first laminate including afirst layer including titanium, titanium alloy, or a combination thereofand a second layer having a density ranging from about 6.0 g/cm³ toabout 8.0 g/cm³. In an alternate embodiment, the first zone includesmonolithic zirconium. The second layer may include steel, steel alloy,or a combination thereof. In this aspect of the invention, the thirdzone may include a laminate including a plurality of layers, and whereinthe laminate has a density less than the first density. In anotherembodiment, the third zone includes monolithic titanium.

The second zone may include a second laminate including a third layerand a fourth layer, wherein the third layer has a third density andincludes titanium, titanium alloy, or a combination thereof, and whereinthe fourth layer has a fourth density less than the third density andincludes aluminum, aluminum alloy, or combinations thereof.

The present invention is also directed to a golf club head thatincludes: a first zone including a body defining an inner volume, sole,and a skirt, wherein the first zone has a density ranging from about 3g/cm³ to about 4 g/cm³, and wherein the first zone is formed from afirst laminate, wherein the first laminate includes a first layer havinga first density and a second layer having a second density less than thefirst density, and wherein the second layer faces the inner volume; asecond zone including a crown; and a third zone including a face.

The first layer may have a density ranging from about 3 g/cm³ to about 4g/cm³ and the second layer has a density ranging from about 2 g/cm³ toabout 3 g/cm³. The first layer may also have a first thickness, whereinthe second layer has a second thickness, and wherein the ratio of thefirst thickness to second thickness ranges from about 1:1 to about 1:4.In one embodiment, the first layer has a first thickness from about 0.1mm to about 0.5 mm, and wherein the second layer has a second thicknessranging from about 0.4 to about 0.8.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description that is provided in connection withthe drawings described below:

FIG. 1 shows a cross-section of one embodiment of a golf club headaccording to the present invention;

FIGS. 2A and 2B shows a side of a component of a golf club headaccording to one embodiment of the present invention; and

FIG. 3 shows an exploded view of a golf club head according to thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to wood-type golf club heads, golf clubs,and the like (such as drivers, fairway woods, hybrids, and/or the like),as well as to methods of making and using such clubs and club heads. Theclub head body member may take on a variety of different forms, shapes,and/or sizes without departing from this invention and includes, but isnot limited to, a club head body member defining an interior chamber, astriking face, a crown portion, and a sole portion.

The club head may be made of a one piece construction or from amulti-piece construction. In a multi-piece construction, the club headbody member is made from multiple components having one or more zonesthat are joined together via welding, brazing, adhesive bonding, orcombinations thereof. In one embodiment, a club head body memberincludes a plurality of zones, each formed with materials or laminateshaving different densities that are joined together. The club head bodymember may include two zones, three zones, four zones, five zones, sixzones, or more than six zones.

While the overall weight of the wood-type golf club head of theinvention will vary depending on the specific type, i.e., driver,fairway wood, hybrid, the use of the materials described herein and themethods of forming the golf club heads of the invention provide amanufacturer the ability to maximize volume, increase COR, adjust MOIand COG by strategically distributing the mass in different zones of theclub head, and improve overall durability of the club head. For example,even through a wood-type golf club head will always be designed to weighbetween about 190 g and 205 g, the specific materials used in the golfclub head allow the maximum volume, COR, and strength with adjustabilityin the MOI and COG for the particular type of wood-type golf club head.

High Density Zones

In certain areas of the club head, high density materials are optimalbecause they spread out mass over a wider area as opposed to a largemass at a localized point. For example, the sole of the golf club head,which suffers repeated impact with the ground, is a portion of the clubhead that requires durable materials and provides design opportunitiesto keep the COG as low or as close to the neutral axis as possible. Thehigh density zones of a club head of the present invention preferablyhave equivalent densities ranging from about 5.5 g/cm³ to about 8 g/cm³.In another embodiment, a high density zone according to the presentinvention has an equivalent density ranging from about 5.75 g/cm³ toabout 7.9 g/cm³. In yet another embodiment, the equivalent densityranges from about 6 g/cm³ to about 7.8 g/cm³. In still anotherembodiment, the high density zones have equivalent densities rangingfrom about 6 g/cm³ to about 7 g/cm³.

The thickness of the high density zones may vary depending on theplacement of the zone in the club head. In one embodiment, the highdensity zone may have an average thickness that ranges from about 0.5 mmto about 2.5 mm. In another embodiment, the average thickness of thehigh density zone may range from about 0.75 mm to about 2.0 mm. In stillanother embodiment, the high density zones have thicknesses ranging fromabout 1.0 mm to about 1.8 mm.

The weight of the high density zone may be from about 30 g to about 50g. In one embodiment, the mass of the high density zone ranges fromabout 30 g to about 40 g. In another embodiment, the mass of the highdensity zone ranges from about 34 g to about 38 g.

The high density zone or zones may comprise about 5 percent to about 40percent of the club head. In one embodiment, the high density zonecomprises about 10 percent to about 30 percent of the club head. Inanother embodiment, the high density zone comprises at least about 15percent of the club head. In still another embodiment, about 15 percentto about 20 percent of the club head comprises one or more high densityzones.

In one embodiment, the high density zone may be formed from a laminatethat includes at least two layers. The high density zone may also beformed from more than two layers. For example, in one embodiment, thehigh density zone includes at least three layers. In another embodiment,the high density zone includes at least four layers. In an alternateembodiment, the high density zone is formed from a single layer.

For example, a high density zone according to the invention may beformed from a first layer having a first density and a first thicknessand a second layer having a second density and a second thickness. Inthis aspect of the invention, the first density may range from about 6.0g/cm³ to about 8 g/cm³. In another embodiment, the first density rangesfrom about 6.5 g/cm³ to about 7.9 g/cm³. In yet another embodiment, thefirst density ranges from about 6.75 g/cm³ to about 7.8 g/cm³. In stillanother embodiment, the first density ranges from about 7.0 g/cm³ toabout 7.8 g/cm³. The second density may range from about 3.5 g/cm³ toabout 5.5 g/cm³. In another embodiment, the second density ranges fromabout 4.0 g/cm³ to about 5.0 g/cm³. In yet another embodiment, thesecond density ranges from about 4.25 g/cm³ to about 4.75 g/cm³. Instill another embodiment, the second density ranges from about 4.3 g/cm³to about 4.5 g/cm³.

The ratio of the first thickness to the second thickness may be fromabout 0.5 to about 4. In one embodiment, the ratio of the firstthickness to the second thickness is about 1 to about 3. In anotherembodiment, the ratio of the first thickness to the second thickness isabout 1 to about 2. The first thickness may range from about 0.5 mm toabout 1.0 mm. In one embodiment, the first thickness ranges from about0.55 mm to about 0.95 mm. In another embodiment, the first thicknessranges from about 0.6 mm to about 0.9 mm. The second thickness mayranges from about 0.1 mm to about 0.8 mm. In one embodiment, the secondthickness ranges from about 0.2 mm to about 0.7 mm. In anotherembodiment, the second thickness ranges from about 0.3 mm to about 0.65mm.

The first and second layers may be made from any material having adensity in the desired range. In one embodiment, the first layer isformed from steel, zirconium, copper, nickel, zinc, chromium, manganese,niobium, molybdenum, hafnium, tantalum, or combinations and alloysthereof. The second layer may be formed from titanium, titanium alloy,aluminum, aluminum alloy, or combinations thereof. For example, a highdensity zone according to the present invention may be formed from afirst layer of stainless steel and a second layer of titanium ortitanium alloy.

Suitable, but not limiting examples of titanium materials for use withthe present invention include alpha or near-alpha titanium alloys suchas Ti-8Al-1V-1Mo, Ti-5Al-1Fe-1Cr-0.7Mo, alpha-beta alloys such asTi-6Al-4V (Ti-6-4), Ti-4.5Al-3V-2Fe-2Mo (SP-700), andTi-5Al-1Sn-1Zr-1V-0.8Mo (Ti-5111), and heat treated beta alloys such asTi-15-3-3-3, Beta C, DAT 51, DAT 55. Other suitable titanium alloysinclude alpha and near-alpha alloys such as Ti-0.3Mo-0.8Ni, Ti-3Al-2.5V,Ti-3Al-2.5V—Pd, Ti-3Al-2.5V—Ru, Ti-5Al-2.5Sn, Ti-5Al-2.5Sn ELI,Ti-8Al-1Mo-1V, and Ti-6Al-2Sn-4Zr-2Mo-0.1Si, alpha-beta alloys such asTi-6Al-4V ELI, Ti-6Al-4V-0.1Ru, Ti-6Al-7Nb, Ti-6Al-6V-2Sn,Ti-6Al-2Sn-4Zr-6Mo, Ti-4Al-4Mo-2Sn-0.5Si, Ti-6Al-2Sn-2Zr-2Mo-2Cr-0.15Si,and Ti-5Al-4Cr-4Mo-2Sn-2Zr, Ti-4Al-2.5V-1.5Fe, Ti-4.5Al-2Mo-1.5V-0.5Fe,Ti-6Al-1.5V-1.5Mo-0.3Fe, Ti-5Al-4V-0.8Mo-0.5Fe, beta and near-betaalloys such as Ti-10V-2Fe-3Al, Ti-3Al-8V-6Cr-4Zr-4Mo, andTi-3Al-8V-6Cr-4Zr-4Mo-0.05Pd, Ti-15Mo-5Zr-3Al, Ti-15Mo-3Al,Ti-20V-3.5Al-1Sn, and Ti-5Al-5Mo-5V-3Cr, and mixtures thereof.

In one embodiment, the high density zone may form at least a part of thesole of the golf club head. For example, as shown in FIG. 1 the solewall 20 may be formed from a high density zone. In another embodiment,at least one other part of the club head is formed form a high densityzone.

When the high density zones are laminate, the laminates may be formedusing any conventional process available to those of ordinary skill inthe art. For example, the laminate may be formed with the cladding orcold roll bonding process to the desired thickness by rolling together asheet of a first material and a sheet of the second material under highpressure to form a metallurgical bond between the two materials.

The laminate sheet may then be used to obtain the required shapes viastamping, water jet cutting, or laser cutting. Once the shapes for thehigh density zones are obtained, they may be warm or hot formed tofabricate the components, which will ultimately be joined together withother components to form the club head via welding, brazing, adhesivebonding, ultrasonic energy, or combinations thereof.

Because the melting point of the material used to form the second layermay be less than the melting point of the material used to form thefirst layer, welding the components together to form the club head maylead to meltdown of the material used to form the second layer.Accordingly, the second layer having a lower melting point may bemachined off along the perimeter of the shape prior to componentfabrication. Alternatively, other forms of welding that generate lessheat, i.e., laser welding or plasma welding, may avoid material meltdownin the second laminate layer.

The club head is preferably formed such that the less dense layer of thelaminate forms the outer layer of the club head and the denser layerforms the inner surface. For example, in one embodiment, the laminate isformed from titanium and steel and the steel forms the inner surface ofthe high density zone.

Low Density Zones

Similar to the need for high density zones, golf club heads also mayinclude low density zones with mass savings spread out over a broadarea. For example, the crown of the golf club head suffers minimalimpact with the ground or ball and, thus, is an area of the club headthat may be formed from low density materials in an effort to manipulatethe overall weight of the club head and the center of gravity of theclub head.

The low density zones of a club head of the present invention preferablyhave equivalent densities ranging from about 2.5 g/cm³ to about 4.5g/cm³. In another embodiment, a low density zone according to thepresent invention has an equivalent density ranging from about 2.75g/cm³ to about 4.0 g/cm³. In yet another embodiment, the equivalentdensity ranges from about 3 g/cm³ to about 3.75 g/cm³. In still anotherembodiment, the low density zones have equivalent densities ranging fromabout 3 g/cm³ to about 3.70 g/cm³.

The thickness of the low density zones may vary depending on theplacement of the zone in the club head. In one embodiment, the lowdensity zone may have an average thickness that ranges from about 0.1 mmto about 1.0 mm. In another embodiment, the average thickness of the lowdensity zone may range from about 0.2 mm to about 0.8 mm. In stillanother embodiment, the low density zones have thicknesses ranging fromabout 0.3 mm to about 0.75 mm.

The weight of the low density zone may be from about 10 g to about 30 g.In one embodiment, the mass of the low density zone ranges from about 15g to about 25 g. In another embodiment, the low density zone ranges inweight from about 18 g to about 22 g. In this aspect of the invention,the low density zone preferably has a weight range that is about 80percent to about 98 percent of the weight range of a Ti-6-4 crown havingthe same dimensions. In one embodiment, the low density zone weightrange is about 83 to about 97 percent of the weight range of a Ti-6-4crown having the same dimensions.

The low density zone or zones may comprise about 20 percent to about 50percent of the club head. In one embodiment, the low density zonecomprises about 25 percent to about 45 percent of the club head. Inanother embodiment, the low density zone comprises at least about 30percent of the club head. In still another embodiment, about 32 percentto about 40 percent of the club head comprises one or more low densityzones.

In one embodiment, the low density zone may be formed from a laminatethat includes at least two layers. The low density zone may also beformed from more than two layers. For example, in one embodiment, thelow density zone includes at least three layers. In another embodiment,the low density zone includes at least four layers. In an alternateembodiment, the low density zone is formed from a single layer.

For example, a low density zone according to the invention may be formedfrom a first layer having a first density and a first thickness and asecond layer having a second density and a second thickness. In thisaspect of the invention, the first density may range from about 3.5g/cm³ to about 5.5 g/cm³. In another embodiment, the first densityranges from about 4.0 g/cm³ to about 5.0 g/cm³. In yet anotherembodiment, the first density ranges from about 4.25 g/cm³ to about 4.75g/cm³. In still another embodiment, the first density ranges from about4.3 g/cm³ to about 4.6 g/cm³. The second density may range from about1.5 g/cm³ to about 4.0 g/cm³. In another embodiment, the second densityranges from about 2.0 g/cm³ to about 3.5 g/cm³. In yet anotherembodiment, the second density ranges from about 2.2 g/cm³ to about 3.0g/cm³. In still another embodiment, the second density ranges from about2.3 g/cm³ to about 2.8 g/cm³.

The ratio of the first thickness to the second thickness may be fromabout 6:1. In one embodiment, the ratio of the first thickness to thesecond thickness is about 1:5. In another embodiment, the ratio of thefirst thickness to the second thickness is about 1:4. In still anotherembodiment, the ratio of the first thickness to the second thickness isabout 1:3. For example, the first thickness to second thickness ratiomay be from about 1:2. In another embodiment, the low density zone has afirst thickness to second thickness ratio from about 1:1. The firstthickness may range from about 0.05 mm to about 0.5 mm. In oneembodiment, the first thickness ranges from about 0.1 mm to about 0.6mm. In another embodiment, the first thickness ranges from about 0.2 mmto about 0.3 mm. The second thickness may range from about 0.2 mm toabout 1.0 mm. In one embodiment, the second thickness ranges from about0.25 mm to about 0.7 mm. In another embodiment, the second thicknessranges from about 0.30 mm to about 0.6 mm.

In one embodiment, the low density zone may form at least a part of thecrown of the golf club head. For example, as shown in FIG. 1 the crown30 may be formed from a low density zone.

In another embodiment, at least one other part of the club head isformed form a second low density zone. For example, as shown in FIG. 1,the second low density zone may form the skirt 40 and, optionally, atleast a portion of the sole 20 of the club head. In this aspect of theinvention, the second low density zone may have an equivalent densityranging from about 2.5 g/cm³ to about 4.5 g/cm³. In another embodiment,the second low density zone according to the present invention has anequivalent density ranging from about 2.75 g/cm³ to about 4.0 g/cm³. Inyet another embodiment, the equivalent density of the second low densityzone ranges from about 3 g/cm³ to about 3.9 g/cm³. In still anotherembodiment, the second low density zone has an equivalent densityranging from about 3.1 g/cm³ to about 3.8 g/cm³.

The thickness of the second low density zone may vary depending on theplacement of the zone in the club head. In one embodiment, the secondlow density zone may have an average thickness that ranges from about0.3 mm to about 1.5 mm. In another embodiment, the average thickness ofthe low density zone may range from about 0.4 mm to about 1.3 mm. Instill another embodiment, the low density zones have thicknesses rangingfrom about 0.5 mm to about 1.0 mm.

The weight of the second low density zone may be from about 30 g toabout 60 g. In one embodiment, the second low density zone ranges inweight from about 35 g to about 50 g. In another embodiment, the secondlow density zone ranges from about 38 g to about 48 g. In this aspect ofthe invention, the second low density zone preferably has a weight rangethat is about 80 percent to about 98 percent of the weight range of aTi-6-4 skirt/sole having the same dimensions. In one embodiment, thesecond low density zone weight range is about 83 to about 97 percent ofthe weight range of a Ti-6-4 skirt/sole having the same dimensions.

The second low density zone or zones may comprise about 40 percent toabout 60 percent of the club head. In one embodiment, the second lowdensity zone comprises about 45 percent to about 55 percent of the clubhead. In another embodiment, the second low density zone comprises atleast about 45 percent of the club head. In still another embodiment,about 45 percent to about 53 percent of the club head comprises one ormore second low density zones.

In one embodiment, the second low density zone may be formed from alaminate that includes at least two layers. The second low density zonemay also be formed from more than two layers. For example, in oneembodiment, the second low density zone includes at least three layers.In another embodiment, the second low density zone includes at leastfour layers. In an alternate embodiment, the second low density zone isformed from a single layer.

For example, a second low density zone according to the invention may beformed from a first layer having a first density and a first thicknessand a second layer having a second density and a second thickness. Inthis aspect of the invention, the first density may range from about 3.5g/cm³ to about 5.5 g/cm³. In another embodiment, the first densityranges from about 4.0 g/cm³ to about 5.0 g/cm³. In yet anotherembodiment, the first density ranges from about 4.25 g/cm³ to about 4.75g/cm³. In still another embodiment, the first density ranges from about4.3 g/cm³ to about 4.6 g/cm³. The second density may range from about1.5 g/cm³ to about 4.0 g/cm³. In another embodiment, the second densityranges from about 2.0 g/cm³ to about 3.5 g/cm³. In yet anotherembodiment second the first density ranges from about 2.2 g/cm³ to about3.0 g/cm³. In still another embodiment, the second density ranges fromabout 2.3 g/cm³ to about 2.8 g/cm³.

The ratio of the first thickness to the second thickness may be fromabout 1:6. In one embodiment, the ratio of the first thickness to thesecond thickness is about 1:5. In another embodiment, the ratio of thefirst thickness to the second thickness is about 1:4. In still anotherembodiment, the ratio of the first thickness to the second thickness isabout 1:3. For example, the first thickness to second thickness ratiomay be from about 1:2. In another embodiment, the low density zone has afirst thickness to second thickness ratio from about 1:1. The firstthickness may range from about 0.1 mm to about 0.6 mm. In oneembodiment, the first thickness ranges from about 0.15 mm to about 0.5mm. In another embodiment, the first thickness ranges from about 0.16 mmto about 0.48 mm. The second thickness may range from about 0.3 mm toabout 1.0 mm. In one embodiment, the second thickness ranges from about0.35 mm to about 0.9 mm. In another embodiment, the second thicknessranges from about 0.40 mm to about 0.8 mm.

The first and second layers in the low density zones may be made fromany material having a density in the desired range. In one embodiment,the second layer is formed from aluminum, aluminum alloy, orcombinations thereof. The first layer may be formed from titanium,titanium alloy, or combinations thereof. For example, a second lowdensity zone according to the present invention may be formed from afirst layer of titanium or titanium alloy and a second layer of aluminumor aluminum alloy.

Suitable, but not limiting examples of titanium materials for use withthe low density zones of the present invention include alpha ornear-alpha titanium alloys such as Ti-8Al-1V-1Mo, Ti-5Al-1Fe-1Cr-0.7Mo,alpha-beta alloys such as Ti-6Al-4V (Ti-6-4), Ti-4.5Al-3V-2Fe-2Mo(SP-700), and Ti-5Al-1Sn-1Zr-1V-0.8Mo (Ti-5111), and heat treated betaalloys such as Ti-15-3-3-3, Beta C, DAT 51, DAT 55. Other suitabletitanium alloys include alpha and near-alpha alloys such asTi-0.3Mo-0.8Ni, Ti-3Al-2.5V, Ti-3Al-2.5V—Pd, Ti-3Al-2.5V—Ru,Ti-5Al-2.5Sn, Ti-5Al-2.5Sn ELI, Ti-8Al-1Mo-1V, andTi-6Al-2Sn-4Zr-2Mo-0.1Si, alpha-beta alloys such as Ti-6Al-4V ELI,Ti-6Al-4V-0.1Ru, Ti-6Al-7Nb, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo,Ti-4Al-4Mo-2Sn-0.5Si, Ti-6Al-2Sn-2Zr-2Mo-2Cr-0.15Si, andTi-5Al-4Cr-4Mo-2Sn-2Zr, beta and near-beta alloys such asTi-10V-2Fe-3Al, Ti-3Al-8V-6Cr-4Zr-4Mo, and Ti-3Al-8V-6Cr-4Zr-4Mo-0.05Pd,Ti-15Mo-5Zr-3Al, Ti-15Mo-3Al, Ti-20V-3.5Al-1Sn, and Ti-5Al-5Mo-5V-3Cr,and mixtures thereof.

Suitable, but not limiting examples of aluminum materials for use withthe low density zone include 1000 series, 2000 series, 3000 series, 4000series, 5000 series, 6000 series, 7000 series and 8000 series aluminumalloys, examples of which are Al 2014, Al 2024, Al 3003, Al 5052, Al5083, Al 6061, Al 6063, Al 7005, Al 7075, Al 8091, and combinationsthereof.

When the low density zones are laminate, the laminates may be formedusing any conventional process available to those of ordinary skill inthe art. For example, the laminate may be formed with the cladding orcold roll bonding process to the desired thickness. In one embodiment,forming the laminate includes rolling together a sheet of a firstmaterial and a sheet of the second material under high pressure to forma metallurgical bond between the two materials.

The laminate sheet may then be used to obtain the required shapes viastamping, water jet cutting, or laser cutting. Once the shapes for thelow density zones are obtained, they may be warm or hot formed tofabricate the components, which will ultimately be joined together withother components to form the club head via welding, brazing, adhesivebonding, ultrasonic energy, or combinations thereof.

Because the melting point of the material used to form the second layermay be less than the melting point of the material used to form thefirst layer, welding the components together to form the club head maylead to meltdown of the material used to form the second layer.Accordingly, the second layer having the lower melting point may bemachined off along the perimeter of the shape prior to componentfabrication. Alternatively, other forms of welding that generate lessheat, i.e., laser welding or plasma welding, may avoid material meltdownin the second laminate layer.

The club head is preferably formed such that the denser laminate layerof the low density zone forms the outer surface of the club head and theless dense layer forms the inner surface. For example, in oneembodiment, the laminate is formed from titanium and aluminum and thealuminum forms the inner surface of the high density zone.

Reinforced Low Density Zones

Certain areas of the club head may be formed from a reinforced lowdensity zone. For example, in one embodiment, a reinforced low densityzone may be formed form a laminate that includes a low density laminateand a reinforcing layer. As shown in FIG. 2A, the reinforced low densityzone 51 may include a low density laminate 52 as discussed above withrespect to the low density zones with a reinforcing layer 56. Inparticular, the low density laminate may have an equivalent densityranging from about 2.5 g/cm³ to about 4.5 g/cm³. In another embodiment,a low density laminate according to the present invention has anequivalent density ranging from about 2.75 g/cm³ to about 4.0 g/cm³. Inyet another embodiment, the equivalent density of the low densitylaminate ranges from about 3 g/cm³ to about 3.75 g/cm³. In still anotherembodiment, the low density laminate has an equivalent density rangingfrom about 3 g/cm³ to about 3.70 g/cm³.

The low density laminate may be formed from a first layer 53 having afirst density and a second layer 54 having a second density. In oneembodiment, the first density is greater than the second density. Forexample, the first density may range from about 3.5 g/cm³ to about 5.5g/cm³ and the second density may range from about 1.5 g/cm³ to about 4.0g/cm³. In another embodiment, the first density ranges from about 4.0g/cm³ to about 5.0 g/cm³ and the second density ranges from about 2.0g/cm³ to about 3.5 g/cm³. In yet another embodiment, the first densityranges from about 4.25 g/cm³ to about 4.75 g/cm³ and the second densityranges from about 2.2 g/cm³ to about 3.0 g/cm³. In still anotherembodiment, the first density ranges from about 4.3 g/cm³ to about 4.6g/cm³ and the second density ranges from about 2.3 g/cm³ to about 2.8g/cm³. The material used to form the first layer may be any of thetitanium materials discussed above with respect to the low density zone.Likewise, in one embodiment, the material used to form the second layerof the low density laminate may be any of the aluminum materialsdiscussed above with respect to the low density zone.

The reinforcing layer 56 may be formed of a material having a density ofabout 4 g/cm³ to about 5 g/cm³. In one embodiment, the reinforcing layer56 is formed from a material having a density of about 4.2 g/cm³ toabout 4.8 g/cm³. In another embodiment, the material used to form thereinforcing layer has a density of about 4.4 g/cm³ to about 4.6 g/cm³.The material used to form the reinforcing layer may be titanium ortitanium alloy.

The reinforced low density zone may be fabricated using a number ofmethods. For example, the laminate may be formed with the cladding orcold roll bonding process to the desired thickness by rolling together asheet of a first material and a sheet of the second material under highpressure to form a metallurgical bond between the two materials. Theresulting laminate sheet may then be used to obtain the required shapesvia stamping, water jet cutting, or laser cutting. Once the shapes forthe low density zones are obtained, the second layer may be machined tofacilitate welding of the reinforcing layer. In particular, as shown inFIG. 2A, the second layer 54 may be machined off along the perimeter ofthe laminate to create a step. The reinforcing layer 56 may be stampedand machined to form a cavity to accommodate the second layer 54. In thealternative, the reinforcing layer 56 may include multiple componentssuch as side walls 57 a and 57 b and base 58 that are joined together.In one embodiment, the side walls and base are formed of the samematerial. In another embodiment, the side walls and base are formed ofdifferent materials.

As further shown in FIG. 2B, the low density laminate 52 and reinforcinglayer 56 may be welded together (for example with weld material 60 alongthe perimeter) and machined to remove excess material. The welding maybe conventional welding, laser welding, plasma welding, or variationsthereof. The low density laminate 52 and reinforcing layer 56 may alsobe joined together via brazing, adhesive bonding, ultrasonic energy, orcombinations thereof.

After the reinforced low density zone is obtained, it may be formed toprovide a bulge and roll if used as a face insert and welded to the faceinsert cavity. Alternatively, the low density laminate 52 andreinforcing layer 56 may be welded into the face cavity simultaneously.

Club Heads Formed From Low and High Density Zones

The club heads of the invention may include at least one high densityzone, at least one low density zone, at least one reinforced low densityzone, and combinations thereof. In one embodiment, the club headincludes a high density zone that forms at least a portion of the sole.In another embodiment, the club head includes a low density zone thatforms at least a portion of the crown. In yet another embodiment, asecond low density zone forms at least a portion of the club head body,skirt, and sole.

In this aspect of the invention, the face may be formed from monolithictitanium. In another embodiment, the face and the area surrounding theface (leading crown and leading sole areas), may be formed frommonolithic titanium. In still another embodiment, the club head mayinclude a reinforced low density zone that forms at least a portion ofthe face.

FIG. 3 shows a portion of a golf club head 100 according to oneembodiment of the present invention. In the illustrated embodiment, theclub head body member 110 may be formed from a first low densitytitanium alloy. The crown 110 is formed form a first low density zone.The face insert 130 is formed from a reinforced low density zone. Theclub head body 120, which includes the skirt and sole for the purposesof this embodiment, may be formed from a second low density zone.

In another embodiment, at least a portion of the club head body 120, isformed from a the second low density zone and at least a second portionof the club head body 120, which includes the sole 124 may be formedfrom a high density zone. In particular, the skirt 122 may be formed ofa second low density zone and the sole 124 may be formed of a highdensity zone.

In such embodiments, the components may be coupled to each other in avariety of manners with ultrasonic energy being one preferred manner. InFIG. 1, the hosel is shown, but is not considered to be part of the clubhead body member. At least one weight port 126 may be used in the clubhead body. Furthermore, while wood-type club heads are illustrated, theinventive embodiments described herein are not intended to be limited tosuch club heads. For example, iron-type club heads may also be designedwith high and low density zones. In particular, in one embodiment, ahigh density zone may be incorporated into at least a portion of thesole of an iron-type club head by using ultrasonic welding.

The high and low density zones may be joined together with the club headbody member (in the respective cavities) via welding, infrared brazing,adhesive bonding, ultrasonic energy, or combinations thereof. The zonesmay be joined together using the same or different methods. As would beappreciated by those of ordinary skill in the art, the type of weldingused to join the components together may be any suitable welding thatresults in a joined product with the least weld material at the jointsand heat affected zones. In this aspect, suitable types of welding foruse with the present invention include, but are not limited to, laserwelding, plasma welding, TIG welding, MIG welding, or combinationsthereof. In one embodiment, the type of welding used to join either orboth of the crown and face components may be laser welding, plasmawelding, or combinations thereof. Without being bound to any specifictheory, laser and plasma welding reduces the amount of material added atthe joint and result in smaller heat affected zones (as compared to TIGwelding).

In another embodiment, at least two zones are joined with ultrasonicenergy. In particular, the use of ultrasonic energy may be used tofabricate a club head with precise joints for maximum performance. Inaddition, because ultrasonic processes do not use or generate more thana minimum amount of heat, the steps discussed above with respect tomachining the second layer to avoid meltdown may be avoided when usingultrasonic energy. Finally, because ultrasonic energy does not result inoxidation or color change, club heads and the components therein thatare bonded with ultrasonic energy will require less finishing (e.g.,grinding and polishing).

The golf club constructions described above may be employed in awood-type golf club. For a metal wood such as a driver or a fairwaywood, the club head has a volume of about 90 cc to about 460 cc.Preferably, the volume of a metal wood club head is at least about 250cc. According to one aspect of the invention, the volume for a hybridclub is between about 100 cc and about 200 cc. In one embodiment, thevolume for a hybrid club is between about 125 cc and 150 cc. In oneembodiment, the volume of a hybrid club according to the presentinvention may be less than 130 cc.

Finishing touches, e.g., painting and sanding, may optionally beperformed for aesthetic purposes.

EXAMPLES

The following examples are provided to illustrate the present invention,and should not be construed as limiting thereof.

Example 1 A High Density Zone

A high density zone may be formed with the zone material and propertiesset forth in Table 1 below.

TABLE 1 HIGH DENSITY ZONE Equivalent Average Laminate Sole Total SoleLaminate Zone Density Sole Weight Thickness Density Thickness ThicknessMaterial (g/cm²) Area (cm²) (g) Ratio (g/cm²) (mm) (cm) steel 7.80 46.0035.88 n/a 7.80 1.00 0.10 Ti 6-4 4.43 46.00 35.88 n/a 4.43 1.80 0.18zirconium 6.40 46.00 35.88 n/a 6.40 1.20 0.12 steel/Ti 7.8/4.43 46.0035.88 1 6.09 1.24 .064/.064 steel/Ti 7.8/4.43 46.00 35.88 2 6.67 1.17.078/.039 steel/Ti 7.8/4.43 46.00 35.88 3 6.96 1.12 .084/.028

When used in a sole of the club head with the area and thicknessdimensions as set forth above, the steel/titanium laminate providescomparable center of gravity and moment of inertia values as themonolithic zirconium and steel materials.

Example 2 Low Density Zone

A low density zone may be formed as set forth in Table 2 below.

TABLE 2 LOW DENSITY ZONE Average Laminate Total Laminate Zone DensityThickness Thickness Thickness Material (g/cm³) Area (cm²) Weight (g)Ratio (mm) (mm) Ti-6-4 n/a 103.1 22.83 n/a 0.5 n/a Laminate 1 3.07 103.119.00 1:5 0.6 0.1/0.5 Laminate 2 3.21 103.1 19.84 1:3 0.6 0.15/0.45Laminate 3 3.34 103.1 20.68 1:2 0.6 0.2/0.4 Laminate 4 3.62 103.1 22.361:1 0.6 0.3/0.3

If the zone materials of Table 2 are used in a crown, the weight savingsusing the laminates of the invention range from about 2 percent to about17 percent as compared to a crown formed from Ti-6-4 (Table 3).

TABLE 3 LOW DENSITY ZONE WEIGHT SAVINGS Zone Material Weight Savings (%)Laminate 1 16.8 Laminate 2 13.1 Laminate 3 9.4 Laminate 4 2.1

Example 3 Low Density Zone

A low density zone may be formed as set forth in Table 4 below.

TABLE 4 LOW DENSITY ZONE Average Laminate Total Laminate Zone DensityThickness Thickness Thickness Material (g/cm³) Area (cm²) Weight (g)Ratio (mm) (mm) Ti-6-4 n/a 139.6 22.83 n/a 0.75 n/a Laminate 5 3.13139.6 39.28 1:4 0.9 0.18/0.72 Laminate 6 3.21 139.6 40.30 1:3 0.90.225/0.675 Laminate 7 3.34 139.6 42.01 1:2 0.9 0.3/0.6 Laminate 8 3.62139.6 45.42 1:1 0.9 0.45/0.45

If the zone materials of Table 2 are used in the body, sole, and skirtwith an overall area as provided in Table 4, the weight savings usingthe laminates of the invention range from about 2 percent to about 16percent as compared to a crown formed from Ti-6-4 (Table 5).

TABLE 5 LOW DENSITY ZONE WEIGHT SAVINGS Zone Material Weight Savings (%)Laminate 1 15.3 Laminate 2 13.1 Laminate 3 9.4 Laminate 4 2.1

Although the present invention has been described with reference toparticular embodiments, it will be understood to those skilled in theart that the invention is capable of a variety of alternativeembodiments within the spirit of the appended claims. For example, golfclub heads in accordance with examples of this invention may includestill additional features, if desired, including features that are knownand used in the art. For example, a golf club head according to theinvention may include a weighting system that is permanently mounted tothe club head body member, e.g., on an interior or exterior of the clubhead body, extending from the exterior to the interior of the club headbody (e.g., through a weight port), etc., or, in the alternative, aweighting system that includes weight member(s) that are movably and/orremovably mounted with respect to the club head body member usingstructures and techniques that are known and used in the art (e.g., byscrew or other mechanical connector attachments, by sliding attachments,etc.). Alternately, the sole may include one or more cavities that arecapable of accommodating inserts having variable weights. In addition,golf clubs according to the invention may include one or more of: (a) ashaft member engaged with the club head body; (b) a grip member engagedwith the shaft, and/or (c) a handle member engaged with the club headand/or the shaft. These additional elements of the golf club structuremay be included in the overall club structure in any desired mannerwithout departing from this invention, including in conventional mannersthat are known and used in the art (e.g., the shaft may be engaged withthe club head body member via an external hosel member, via an internalhosel member, through an opening provided in the club head, viaadhesives, and/or via mechanical connectors.

1. A golf club head, comprising: a first zone comprising a body definingan inner volume, sole, and a skirt, wherein the first zone has a firstdensity ranging from about 3 g/cm³ to about 4 g/cm³, and wherein thefirst zone is formed from a first laminate, wherein the first laminatecomprises a first layer and a second layer, and wherein the second layerfaces the inner volume; a second zone comprising a crown, wherein thesecond zone is formed from a second laminate having a second densityranging from about 3 g/cm³ to about 4 g/cm³, wherein the second laminateis different from the first laminate; and a third zone comprising aface, wherein the third zone comprises a third laminate comprising threelayers.
 2. The golf club head of claim 1, wherein the second density isdifferent from the first density.
 3. The golf club head of claim 1,wherein the first layer has a density ranging from about 3 g/cm³ toabout 4 g/cm³ and the second layer has a density ranging from about 2g/cm³ to about 3 g/cm³.
 4. The golf club head of claim 1, wherein thefirst layer has a first thickness from about 0.1 mm to about 0.5 mm, andwherein the second layer has a second thickness ranging from about 0.4to about 0.8.
 5. The golf club head of claim 1, wherein the first layerhas a first thickness, wherein the second layer has a second thickness,and wherein the ratio of the first thickness to second thickness rangesfrom about 1:1 to about 1:4.
 6. The golf club head of claim 1, furthercomprising a weight.
 7. The golf club head of claim 1, wherein thesecond laminate comprises a third layer having a third density and afourth layer having a fourth density, wherein the fourth density is lessthan the third density, and wherein the fourth layer faces the innervolume.
 8. The golf club head of claim 7, wherein the third layer has athird thickness and the fourth layer has a fourth thickness, and whereinthe fourth thickness is greater than the third thickness. 9.-16.(canceled)
 17. A golf club head, comprising: a first zone comprising abody defining an inner volume, sole, and a skirt, wherein the first zonehas a density ranging from about 3 g/cm³ to about 4 g/cm³, and whereinthe first zone is formed from a first laminate, wherein the firstlaminate comprises a first layer having a first density and a secondlayer having a second density less than the first density, and whereinthe second layer faces the inner volume; a second zone comprising acrown; and a third zone comprising a face.
 18. The golf club head ofclaim 17, wherein the first layer has a density ranging from about 3g/cm³ to about 4 g/cm³ and the second layer has a density ranging fromabout 2 g/cm³ to about 3 g/cm³.
 19. The golf club head of claim 17,wherein the first layer has a first thickness, wherein the second layerhas a second thickness, and wherein the ratio of the first thickness tosecond thickness ranges from about 1:1 to about 1:4.
 20. The golf clubhead of claim 17, wherein the first layer has a first thickness fromabout 0.1 mm to about 0.5 mm, and wherein the second layer has a secondthickness ranging from about 0.4 to about 0.8.
 21. The golf club head ofclaim 1, wherein the first laminate comprises a cladding bond betweenthe first and second layers.
 22. The golf club head of claim 1, whereinthe first layer comprises titanium, titanium alloy, or combinationsthereof and the second layer comprises aluminum, aluminum alloy, orcombinations thereof.
 23. The golf club head of claim 17, wherein thefirst laminate comprises a cladding bond between the first and secondlayers.
 24. The golf club head of claim 17, wherein the first layercomprises titanium, titanium alloy, or combinations thereof and thesecond layer comprises aluminum, aluminum alloy, or combinationsthereof.
 25. A golf club head, comprising a body defining an innervolume, a sole, a skirt, a crown, and a face, wherein the crowncomprises a first laminate, wherein the first laminate has a densityranging from about 2.5 g/cm³ to about 4.5 g/cm³, wherein the skirt and,optionally, the sole, comprises a second laminate, wherein the secondlaminate has a density less than the density of the first laminate andranging from about 2.5 g/cm³ to about 4.5 g/cm³, and wherein the firstlaminate comprises a first layer having a first density and a secondlayer having a second density less than the first density, wherein thesecond layer faces the inner volume, and wherein the first and secondlayers are joined by a cladding bond.
 26. The golf club head of claim25, wherein the first layer comprises titanium, titanium alloy, orcombinations thereof and the second layer comprises aluminum, aluminumalloy, or combinations thereof.
 27. The golf club head of claim 25,wherein the first laminate has a density ranging from about 2.75 g/cm³to about 4.0 g/cm³.
 28. The golf club head of claim 27, wherein thesecond laminate comprises a first layer having a first density and asecond layer having a second density less than the first density,wherein the second layer faces the inner volume, and wherein the firstand second layers are joined by a cladding bond.